000
AXPZ20 KNHC 230901
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0901 UTC Mon Oct 23 2017

Tropical Weather Discussion for the eastern Pacific Ocean from
the Equator to 32N, east of 140W. The following information is
based on satellite imagery, weather observations, radar, and
meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
0900 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Storm Warning:
High pressure building across eastern Mexico in the wake of a
cold front has helped tighten the pressure gradient over the
area. In response to this tighter pressure gradient, northerly
flow funneling through the Chivela pass is reaching near gale
force in the Gulf of Tehuantepec. Winds will further increase to
gale force by early this morning as the cold front moves through
the western Gulf of Mexico. Winds are forecast to further
increase to storm force Tuesday night, with seas building to near
22 ft by midweek. The storm force winds should diminish Wednesday
evening, with gale force winds then persisting into early
Thursday morning. High pressure centered over the Gulf of
Mexico will shift northeast. This will loosen the pressure
gradient over the area as well as veer winds over the southwest
Gulf of Mexico. In response to the weakened pressure gradient, 
winds over the Gulf of Tehuantepec will further diminish to fresh
to strong Thursday, then to 20 kt or less by Friday.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough extends from 10N84W to 08N110W to 08N117W. 
The ITCZ extends from 08N117W to 09N140W. Scattered moderate
convection was noted within 120 nm north of the ITCZ between 119W
and 128W. Scattered moderate isolated strong convection was noted
within 60 nm either side of the ITCZ west of 133W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Please see the special features section above for information on
a developing storm event in the Gulf of Tehuantepec.

Seas in the Baja California offshore waters continue in the 7 to
10 ft range. Seas will continue to gradually subside to less 
than 8 ft off Baja California Sur and within 200 nm of the coast 
of Baja California Norte through late today. Gentle breezes 
associated with a weak pressure pattern along with slight to 
moderate seas will prevail by late week. 

High pressure over the Great Basin region of the western United 
States is maintaining fresh to strong winds over the Gulf of 
California. These winds are expected to continue through 
Tuesday, before diminishing as the area of high pressure shifts 
eastward and the pressure gradient weakens. Winds will be the 
strongest today, with seas peaking near 8 ft.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...
   
Gentle to moderate winds will prevail over the forecast area the
next several days, increasing to moderate to fresh S of the 
monsoon trough by Monday afternoon, and becoming strong S of 
western Panama by Tuesday. NW swell originating from the Gulf of 
Tehuantepec will propagate into the offshore waters of Guatemala 
and El Salvador by the middle of next week. Broad low pressure 
may develop along the monsoon trough by the end of the week, 
drifting to the NW. 

REMAINDER OF THE AREA...

Large NW swell continues to subside over the area, with peak seas
near 10 ft. Seas will continue to subside, to less than 8 ft, by
mid week with tranquil marine conditions expected by the end of 
the week.

$$
AL